A typical telecommunication subscriber often has a plurality of customer premise equipment (CPE) through which the subscriber may be reached. FIG. 3 depicts a typical telecommunication subscriber 50 and possible access networks subscribed to by subscriber 50 (or employer, family, etc.). Subscriber 50 subscribes to or utilizes a plurality of access networks 52, 54, 56, 58 to which a plurality of CPE 60, 62, 64, 66, 68, 70, 72 are connected via a wired or wireless interface. Specifically, telephone 60 and fax machine 62 are connected to a local access network, such as plain old telephone (POT) network 52; mobile-telephone 64 is connected to mobile-telephone communication system 54; telephone 70, personal computer 68 and fax machine 66 are connected to a local access network, such as integrated subscriber digital network (ISDN) 56; and television 72 is connected to cable network 58. Each of the plurality of CPE 60, 62, 64, 66, 68, 70, 72 has its own or shares a destination address, such as a telephone number or e-mail address, for identifying the subscriber. A calling party desiring to reach the subscriber dials or inputs one of the destination addresses associated with the subscriber. However, if the subscriber is not co-located with the CPE associated with the dialed or inputted destination address, then the calling party will not reach the subscriber in real-time. Accordingly, location information regarding the subscriber becomes ever increasingly important if the calling party is to reach the subscriber in real-time, wherein location information indicates a CPE and/or access network at which the subscriber may be reached in real-time.
In wired access networks, such as local access networks and long distance networks, location information is not available in any form. Thus, if the subscriber is not co-located with the subscriber's wired access network CPE, then the subscriber cannot be reached in real-time at that CPE through the associated wired access network. For example, if the calling party calls the subscriber's home telephone when the subscriber is either at work or on the road, the calling party will not be able to reach the subscriber in real-time.
In wireless access networks, location information is available for mobile-telephone communication systems in the form of a home location register (HLR). The HLR includes location information that indicates which mobile-telephone communication system, if any, is currently serving an associated CPE of a subscriber. That is, if the subscriber's CPE is a mobile-telephone, the HLR of the mobile-telephone communication system subscribed to by the subscriber, i.e., home system, will indicate the mobile-telephone communication system currently serving the subscriber's mobile-telephone even if the mobile-telephone is being served by another mobile-telephone communication system other than the one subscribed to by the subscriber (i.e., roaming system). Such location information in the HLR is used by the home system to reach the subscriber at the associated mobile-telephone and complete the call. However, if the subscriber's mobile-telephone is not currently being served by any mobile-telephone communication system, such as when the subscriber's mobile-telephone is powered off, the calling party will not be able to reach the subscriber in real-time at the subscriber's mobile-telephone through the home system. In effect, when the subscriber is not using any mobile-telephone communication system, the subscriber is essentially not co-located with the mobile-telephone since the subscriber cannot be reached in real-time through the home system. Accordingly, there exists a need for locating subscribers in real-time when the subscriber is not co-located with the CPE being called.